1. Field of the Invention
The present invention relates to a light guide plate and a backlight module using the same, and in particular to a light guide plate configured with prisms and grooves.
2. General Background
Because a liquid crystal display (LCD) device has the merits of being thin, light in weight, and drivable by a low voltage, it is extensively employed in various electronic devices.
A liquid crystal panel of an LCD device cannot itself emit light beams. Therefore a typical liquid crystal panel uses a backlight module to provide the needed illumination. The backlight module has a light source and a light guide plate. The light source emits the light beams to the light guide plate, which then transmits the light beams to illuminate the liquid crystal panel.
Referring to FIG. 10, a typical backlight module 10 is shown. The backlight module 10 includes a light guide plate 12 and a light source 13. The light guide plate 12 has a bottom surface 15 and an emitting surface 14. The light source 13 is arranged adjacent to a corner of the light guide plate 12. A plurality of parallel V-shaped grooves 16 are arranged at the bottom surface 15. The V-shaped grooves 16 are arc-shaped. The V-shaped grooves 16 all have a same width and a same height. Moreover, a density of the V-shaped grooves 16 is uniform along a direction away from the light source 13.
When light beams emitted by the light source 13 enter the light guide plate 12, the incident light is reflected at the V-shaped grooves 16. Part of the incident light is reflected in directions corresponding to a viewing angle, and transmits out from the emitting surface 14. Another part of the incident light is reflected in directions such that the reflected light is further reflected by the emitting surface 14. Such light beams reflected from the emitting surface 14 undergo further reflection within the light guide plate 12, and may be completely lost and wasted. Therefore, the light guide plate 12 may have low brightness and low utilization of light energy.
What is needed, therefore, is a light guide plate which can provide highly efficient utilization of light beams.